Fluid flow devices are already well known in the prior art and they exist in forms where an indicator will move in accordance with the rate of flow and will indicate that rate of flow on a scale adjacent the indicator. An example of that prior art device which also incorporates a magnet for moving the indicator is disclosed in U.S. Pat. No. 3,805,611. That prior art is simply a fluid flow meter which visually indicates the rate of flow of fluid through the meter and it does so by means of a movable piston within the meter and a magnet attached to the piston and thus effective for moving an indicator on the exterior of the meter housing.
Further aspects of the prior art include flow meters which have light rays and which have electric means for tracking the movement of a piston or the like and thus indicating the rate of flow. Such prior art is shown in U.S. Pat. Nos. 2,325,884 and 3,218,853. Still further, the prior art includes a flow meter with a movable piston having a magnet and having a follower indicator and also having an electric switch which is actuated by the movement of the indicator. In that instance, the indicator is simply a cylindrical piece which slides over the meter housing, in accordance with the rate of flow, and its movement contacts a switch arm for controlling the electric switch. That is, that prior art is like that shown in U.S. Pat. No. 3,805,611 where the cylindrical indicator would move into contact with a switch arm and the switch would thus be in one switch position when not contacted by the arm and in another switch position when contacted by the arm and thus there were only those two extremes for the switch in that the switch was immediately moved from one position to another by the leading edge of the cylindrical indicator as it moved toward or away from the switch arm. For the present record, that prior art is further disclosed by means of a blueprint drawing submitted herewith.
The prior art also had the further concern that the adjustment of the switches, that is the point at which the switch would actually move from say an "off" position to an "on" position, was difficult to make in any accurate manner, and it was also susceptible to tampering with adjustment since the adjustments for the switches extended to the exterior of a container surrounding the meter itself. Still further, the switches of the prior art were required to be physically displaced to a degree where the wires extending to the switches were a problem in that they needed to be sufficiently sturdy and long and disposed so that they could accommodate the required displacement of the switch in the adjustments mentioned. Still further, where the prior art has its switch arms clear of the indicator which in turn is moved by magnetic power, the switch arm could actually interfere with the true and accurate movement of the magnetic follower indicator when the switch arm and the indicator would come into initial contact. That is, the switch arm could retard the movement of the indicator in either of its moving directions and thus there would be an inaccurate position of the indicator and a consequent inaccurate indication of the rate of flow through the meter. The considerations of wear and reliability of that type of prior art indicator presented a problem compared to the arrangement in the present invention.
The present invention improves upon the prior art in that it provides a fluid flow device wherein an electric switch can be disposed adjacent a tapered member which moves in accordance with the rate of flow through the meter, and the switch arm is always in contact with the tapered surface and thus the problems of impeding the movement of the tapered surface or creating great stress and wear with respect to the switch arm are not present in this invention. Accordingly, the present invention provides for a more accurate control of the electric switch, or switches, which are operated by means of the tapered member.
Other objects and advantages will become apparent upon reading the following description.